On the court, any diagnosis is preliminary and uncertain. He could have had a partially torn achilles, or somesuch.
But this happens with all sorts of leg and foot injuries.
The guy limps off with some support from teammates.
Or if it's real bad they carry the gimp.
It's so bizarrely low-tech and pedestrian compared to the rest of the sophisticated, high-end NBA. Such a weird disconnect. It's almost comical.